Extinction and food-reinforced inhibition of conditioned salivation in dogs

The present experiment compared two methods of eliminating a classically conditioned response in dogs, extinction and reinforcement of nonsalivation, using both a within- and between-subjects experimental design. Eighteen dogs were trained for 16 days in Phase I, 16 days in Phase II, and 8 days in Phase III. In Phase I, each subject received classical conditioning training to two stimuli. In Phase II, Group 1 received extinction training to one stimulus and reinforcement of nonsalivation to the other stimulus. Group 2 received continued classical conditioning training to one stimulus and reinforcement on nonsalivation training to the other. Group 3 received continued classical conditioning training to one stimulus and extinction training to the other. In both the within- and between-subjects comparisons, responding to the stimulus associated with extinction was eliminated faster than responding to the stimulus associated with reinforcement of nonsalivation.     

„Jeder Schule ihre Lehrer“?

Neue Personalauswahl- und Einstellungsverfahren, an denen die Einzelschulen ma?geblich beteiligt werden, kommen bei der Besetzung von Lehrerstellen in zahlreichen Bundesl?ndern seit Mitte der 1990er-Jahre zur Anwendung und haben mittlerweile die herk?mmlichen zentralen Auswahl- und Zuweisungsverfahren zumindest in einigen von ihnen nahezu vollst?ndig abgel?st. Die Praxis und Wirkung der neuen Auswahlverfahren wurde bislang allerdings nicht systematisch untersucht. In diesem Beitrag werden empirische Befunde einer Untersuchung von Schulen in Nordrhein-Westfalen vorgestellt, die im Jahr 2002 freie Lehrerstellen über das neue Ausschreibungsverfahren besetzt haben. Erfasst wurden unter anderem die in der Praxis angewandten Kriterien der Personalauswahl und die Inhalte der Auswahlgespr?che, die Beurteilung des neuen Auswahl- und Einstellungsverfahrens durch die beteiligten Schulleitungen und Mitglieder der Auswahlkommissionen, Einsch?tzungen und Erfahrungen der neu eingestellten Lehrkr?fte sowie der Verlauf ihrer Berufseinstiegsphase und ihre Bew?hrung am neuen Arbeitsplatz.     

Deaf teacher candidates in hearing classrooms: a unique teacher preparation program

An undergraduate teacher education program at Gallaudet University prepares deaf students in "regular" education. This includes a required full-time internship with hearing students (assisted by sign language interpreters). Graduates then continue in a master's degree program in deaf education, thus acquiring dual certification. Several studies indicate that these deaf candidates progress through the same developmental stages as hearing candidates and that they develop high expectations for deaf learners. Issues related to implementing such a program are discussed.     

Student Teachers Meet Ethnic Families

Sixty preservice teachers participated in a program which allowed them to research one ethnic culture, to spend one day as a participant observer in the life of an ethnic family, and to explore the similarities and differences between cultures and within cultures based on their own experience and the feedback of experts. Students self‐reported quantitative gains in empathy, self‐development, understanding of the relevance of multiculturalism in education and confidence to teach the culturally different. Qualitative change in attitudes indicated a decrease in stereotypic thinking, greater understanding of ethnic parents and children and a willingness to make further contact with people from diverse cultures. Benefits to participating hosts are also discussed.     

Houston Teaching Academy: Partnership in developing teachers

The need for excellent teachers to teach at-risk inner-city children is well documented. Too often new teachers who have received their field experience in the suburbs are hired to teach in multicultural inner-city schools with little preparation to serve this population of children and families. Changing the history of failure for this population of teachers and their students to an experience of success was the primary goal of the partnership between the Houston Independent School District and the University of Houston's College of Education.The structure of the Houston Teaching Academy (HTA) includes four collaborative decision-making councils. Representatives from the school and college serve on each of the councils. Shared weekly seminars for supervising teachers, student teachers, and college supervisors are led by school teachers or college supervisors. Methods courses are taught at the HTA, and the students serve as tutors in the classrooms. Several graduate college courses requested by teachers are offered at the HTA.Concurrent with the development of the HTA, a formative and summative evaluation has monitored the progress of the HTA toward its goals. The HTA graduates have been followed into their first years of teaching. Interviews with their principals indicate that 77% are effectively teaching in inner-city and multicultural settings.     

Teaching Traditions in Science Teachers’ Practices and the Introduction of National Testing

Our main interest in this article is to explore whether Swedish teachers changed their teaching and assessment practices in relation to the new national tests in science education that were introduced 2009. Data was collected using a web-distributed questionnaire, which was answered by 407 teachers. The concept of teaching traditions is used to capture patterns of what is emphasized by teachers in terms of goals and content in teaching and the design of the questionnaire was based on the concept of curriculum emphases. The results show two distinct groups of focus, which are compared with two traditions within science education: the Academic and the Moral tradition. The main content where teaching has been changed is in making science more applied than before, where applied not only means the application of science knowledge to practical technical issues, but also to moral and political issues.     

Optimal pruning for tree-structured vector quantization

Tree-structured vector quantization (VQ) is a technique designed to represent a codebook that simplifies encoding as well as vector quantizer design. Most design algorithms for tree-structured VQ used in the past are based on heuristics that successively partition the input space. Recently, Chou, Lookabaugh and Gray proposed a tree-pruning heuristic in which a given initial tree is pruned backwards according to certain optimization criterion. We define the notion of an optimal pruned tree subject to a cost constraint and study the computational complexity of finding such an optimal tree for various cost functions. Under the assumption that all trees are equally probable, we show that, on the average, the number of pruned trees in a given tree is exponential in the number of leaves. Furthermore, we prove that finding an optimal pruned tree subject to constraints such as entropy or the expected-depth is NP-hard. However, we show that when the constraint is the number of leaves, the problem can be solved in polynomial time. We develop an algorithm to find the optimal pruned tree in O(nk) time, where n is the size of the initial tree and kis the constraint size.     

Assessing basic research: Some partial indicators of scientific progress in radio astronomy

As the costs of certain types of scientific research have escalated and as growth rates in overall national science budgets have declined, so the need for an explicit science policy has grown more urgent. In order to establish priorities between research groups competing for scarce funds, one of the most important pieces of information needed by science policy-makers is an assessment of those groups' recent scientific performance. This paper suggests a method for evaluating that performance.After reviewing the literature on scientific assessment, we argue that, while there are no simple measures of the contributions to scientific knowledge made by scientists, there are a number of ‘partial indicators’ — that is, variables determined partly by the magnitude of the particular contributions, and partly by ‘other factors’. If the partial indicators are to yield reliable results, then the influence of these ‘other factors’ must be minimised. This is the aim of the method of ‘converging partial indicators’ proposed in this paper. We argue that the method overcomes many of the problems encountered in previous work on scientific assessment by incorporating the following elements: (1) the indicators are applied to research groups rather than individual scientists; (2) the indicators based on citations are seen as reflecting the impact, rather than the quality or importance, of the research work; (3) a range of indicators are employed, each of which focusses on different aspects of a group's performance; (4) the indicators are applied to matched groups, comparing ‘like’ with ‘like’ as far as possible; (5) because of the imperfect or partial nature of the indicators, only in those cases where they yield convergent results can it be assumed that the influence of the ‘other factors’ has been kept relatively small (i.e. the matching of the groups has been largely successful), and that the indicators therefore provide a reasonably reliable estimate of the contribution to scientific progress made by different research groups.In an empirical study of four radio astronomy observatories, the method of converging partial indicators is tested, and several of the indicators (publications per researcher, citations per paper, numbers of highly cited papers, and peer evaluation) are found to give fairly consistent results. The results are of relevance to two questions: (a) can basic research be assessed? (b) more specifically, can significant differences in the research performance of radio astronomy centres be identified? We would maintain that the evidence presented in this paper is sufficient to justify a positive answer to both these questions, and hence to show that the method of converging partial indicators can yield information useful to science policy-makers.